ESTABL ISHMENT OF DIELECTRIC SPECTROSCOPY FOR INSTANTANEOUS EVALUATING MYOCARDIAL VIABILITY

这项工作的目的是建立用于瞬时评估心肌存活的介电谱。犬心脏分别用4ﾟC生理盐水(S组)和4ﾟC UW液(U组)浸泡8h。间歇性测定心肌tan Delta损失率峰值(Tan Deltam)。并与每隔2小时测定心肌组织三磷酸腺苷的变化进行比较。在保存过程中，心肌细胞的tATP值变化与tATP值的变化具有良好的相关性[S组：r2=0.81，U组：r^2=0.6 6]。将保存的猪心浸泡在4ﾟC生理盐水中，间歇性地测量心脏的tan Delta。随后进行了异位心脏移植。在保存过程中(150~360分钟)，tan Delta(Tan Delta M)峰值由5.5(Sys+-)逐渐降低。[)0.5至3.8()系统+-。[]0.8再灌流后2小时，保存结束时的tan deltam与左心室Emax恢复率(%Emax)呈正相关(r=0.85)，而保存时间与其无相关性(r=0.37)。并将保存过程中TAM的变化与电子显微镜下观察到的心肌结构变化进行比较。心肌细胞膜结构的改变与心肌细胞膜结构的破坏有关，心肌的介电谱可以反映保存过程中细胞的缺血性损伤。Tan deltam可作为即刻评价心肌存活性和预测再灌流后心肌收缩能力的有用参数。

The aim of this work is to establish the dielectric spectroscopy for instantaneous evaluating myocardial viability. Canine hearts were immersed in 4ﾟC saline solution (group S) and 4ﾟC UW solution (group U) for 8 hours. We measured the peak value of tan delta loss tangent (tan delta m) of myocardium intermittently. In addition, changes of tan delta were compared with changes of myocardial ATP measured every 2 hours. During preservation the change of tan delta m (%tan delta m) correlated well with the change of ATP (%ATP) [group S : r^2=0.81, group U : r^2=0.66].And we examined whether tan delta couldpredict ventricular contractility after reperfusion. Preserved porcine hearts were immersed in 4ﾟC saline solution, and tan delta were measured intermittently. Then heterotopic cardiac transplantation followed. During preservation (150 to 360 minutes), the peak value of tan delta (tan delta m) decreased gradually from 5.5(]SY.+-。[)0.5 to 3.8(]SY.+-。[)0.8.Two hours after reperfusion, the tan delta m at the end of preservation was correlated with the percent recovery of left ventricular Emax (%Emax) (r=0.85), while preservation time was not correlated with it (r=0.37). And, changes of tan delta during preservation were compared with myocardial structural changes observed by electron microscopy. The change of tan delta m correlated with the destruction of cellular membrane structure.Dielectric spectroscopy of myocardium can reflect ischemic injury of cell during preservation. The tan delta m may be useful parameter for evaluation of myocardial viability instantaneously and prediction of the ventricular contractility after reperfusion.